1. Field of the Invention
The present invention relates to an object-oriented system that exchanges messages between objects to carry out processing, and particularly to an object-oriented parallel processing system that uses a plurality of processors to carry out parallel processing.
2. Description of the Prior Art
In recent years, the object-oriented systems are being used in knowledge bases, CAIs and prototype making. The object-oriented systems are expected to rapidly progress in various fields.
In the object-oriented system, messages are sent and received between objects having certain functions and knowledges to carry out processes such as arithmetic operations.
When one of the objects receives a message, the object carries out an operation (a message procedure) corresponding to the message and, if necessary, returns a result of the operation. Each object has a region where internal states (instance variables) of the object itself are stored and where the other objects are not allowed to access. The objects comprise concept objects that represent concepts and instance objects that represent instances of the concept objects. The concepts are clearly separated from the instances.
One feature of the object-oriented system is an inheritance. With respect to a certain concept object, there is defined an upper concept object that has a concept more abstractive than a concept held by the certain concept object, and the certain object can inherit the functions (message procedures) and knowledges (instance variables) of the upper concept object to utilize them. For example, a concept object "cheetah" may inherit functions and knowledges from its upper concept objects "mammal", "carnivore" and "animal".
The object-oriented system is essentially appropriate for carrying out parallel processing. Namely, the system exchanges messages between objects that are highly independent of each other and provided with computing substances. However, although the system has the parallel processing ability, the system has a drawback that its processing speed is slow, because it is conventionally operated on a single sequential computer.
With the development of high function high-speed processors, object-oriented parallel processing machines have been proposed. However, the conventional machines do not distinguish concept objects from instance objects and do not realize inheritance mechanisms. Due to this, there are the problems of double codes and complicated descriptions.
In addition, since the conventional object-oriented systems are realized on single exclusive sequential computers as mentioned before, they need a long execution time.